Soft ice

ABSTRACT

The invention relates to composition for use in preparation of cold packs which are useful for medicine, research and other uses where cooling to a low temperature is required, said composition comprising 70-85% water, 4-10% salt, 8-15% glycerine and 2-6% polyacrylamide.

FIELD OF THE INVENTION

This invention relates to a preferred composition for use in preparationof flexible cold packs which are useful for medicinal, research andother uses where cooling to low temperatures is required. The inventionwas previously disclosed in Provisional Patent Application 60/008,902,Dec. 19, 1995.

BACKGROUND OF THE INVENTION

There is presently need for cold packs that will be flexible whilstmaintaining very low temperatures. Several approaches have been tried toprovide packs that will meet the needs for both flexibility andsufficiently low temperatures for long periods of time for medical,industrial, research and recreational applications.

U.S. Pat. No. 4,240,436 to Singleton, which is incorporated herein inits entirety by reference, discloses a disposable perineal ice packparticularly adapted for treatment of swelling and other disfunction inthe rectal-vaginal pelvis region. The pack is composed of a flexiblehollow synthetic material having a cold temperature storage medium suchas water or other liquid freezable material that freezes at between 0°F. and 32° F. The pack is specialized and expensive to produce and use.An alcohol/water slurry is suggested for use to fill the pack disclosedtherein.

U.S. Pat. No. 4,951,666 to Inman, et al., which is incorporated hereinin its entirety by reference, teaches a thermal pack for use in treatinga localized injury. The pack includes a porous outer bag and anon-porous inner bag which is foldable between a retracted positionwithin the outer bag and an extended position in which the inner bagprotrudes from the outer bag for filling. A flap extends from the openmouth of the inner bag to create a funnel for filling the inner bag.Flexibility of the bag depends on the shape of the bag. The bag isparticularly adapted for use on the extremities. There is no teaching ofhow to use the bag using a flexible filling material that is flexiblebelow the freezing temperature of water.

U.S. Pat. No. 5,109,841 to Hubbard, et al., which is incorporated hereinin its entirety by reference, discloses an ice pack for use around theface. The pack comprises a waterproof envelope having a sealable openend and a closed end. A strap is attached at one end of the waterproofenvelope and has a centrally disposed longitudinal slit. No method ofrendering the pack flexible at very low temperatures by use of flexibleice is disclosed therein.

U.S. Pat. No. 5,133,348 to Mayn, which is incorporated herein in itsentirety by reference, discloses a pack which may be filled with hotwater or cold water or ice. The pack has four radially extendingportions attached thereto and integral therewith. The pack isparticularly useful for application to a curved contour of the body.

None of the packs claimed teach use of a cold filling which is flexibleat temperatures below the freezing point of water. None of the referencepacks disclosed is useful without refilling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pack of the invention.

FIG. 2 shows a cross-section of a pack of the invention.

FIG. 3 shows a shipping container with compartments for holding packagesof soft ice.

FIG. 4 shows a view of the supporting grid.

FIG. 5 shows an elongated pack.

FIG. 6 shows a pack having 4 extensions.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention provides a filing material (referred to herein as"soft ice") for use in making cold packs which are appropriate forlaboratory, medical, industrial or home uses. The soft ice compositionsare inexpensive and do not change state under high temperatures. Becausethe compositions of the invention remain flexible at low temperatures to-7° C., the packs of the invention may be made in several varying shapesand provide cushioning effect which is particularly valuable for makingpacks to be used to transfer easily broken materials such as vials ofbiological materials.

The compositions of the invention contain the following materials:

70% to 85% water

4% to 10% salts

8-15% glycerins

1-5% polyacrylamide

Preferred salts include chlorides, sulfates and sulfites. Theformulations are prepared by dissolving the salts in the water, thenadding the glycerine and polyacrylamide to the water and mixing until acolloidal composition is obtained.

EXAMPLE 1

To 690 grams of water was added 175 grams sodium sulfate with mixinguntil the sulfate had been dissolved. 50 grams glycerine and 70 gramspolyacrylamide were then added to the water/salt solution and the wholewas mixed until a colloidal composition was obtained.

Sufficient soft ice mixture was placed in a bag made of flexiblenon-porous material to provide a package about 1 cm thick. Thecomposition was frozen at about -5° C. over night. The packagecontaining the "ice" was removed from the freezer and wrapped around atest tube containing a biological sample.

Particularly preferred packaging allows maximum flexibility whilstproviding protection for the material being cooled using the pack. Apreferred packaging material consists of a waterproof inner layercovered with a porous layer. The inner and outer layer of the packagingmay be laminated to each other. Packs of the invention may be equippedwith extensions such as tabs and ties for use in holding the packsagainst the material to be cooled. Extensions may have fastening meanssuch as hooks and eyes, VELCRO™ or straps and buckles to provide meansfor holding the packs in place. Packs of the invention are useful formedical treatment to stop bleeding, relieve pain and constrict bloodvessels. If the packs become too hardened for the particular use, theymay be softened by kneading with the hands.

The packs of the invention will allow a researcher to retain an easilydegraded sample on the laboratory table top for several hours after thesample has been removed from the freezer. Packs of the invention areparticularly useful for storage of vaccines in the clinical setting whenlarge numbers of individuals are to be treated at one time.

The packs of the invention are also useful for shipping short distanceswhen refrigerated carriers are not available for use. For example, whenanimals are shipped short distances, packs containing soft ice may beplaced over a grid support in the compartments to keep the animals cool.It is also possible to place fans under the supports to circulate theair. In fact, one of the problems that may arise when laboratory animalsare shipped in air-conditioned compartments is that the refrigerationunites may contain infectious organisms if those units are not properlycleaned. The use of soft ice packs which can be refrozen in conjunctionwith more easily cleaned fans may prevent infection of the animals.

In many parts of the world, there are few if any, carriers with airconditioned compartments. Under such circumstances, the compartments maybe divided to provide an area for very large packages containing softice. After use, the soft ice packs may be refrozen for reuse.

Relatively small packs of the invention may be used placed in smallercontainers for transportation of heat-sensitive materials.

Referring to FIG. 1, the packaging may be in the form of a cushion.Referring to FIG. 2, the packaging consists of a porous outer layer (1),and an inner non-porous layer (4). The porous layer forms an edge (2)and the porous layer forms a space (5) for holding the colloidal "softice". The packaging may contain areas lacking in the colloidal fillingmaterial (3). Such areas further stabilize and strengthen the over-allpad. The outer porous layer provides strength to the packaging andcauses the packs to be more comfortable to the touch. The areas lackingcolloidal filling material also cause the total package to be moreflexible.

Referring to FIG. 3, the container (10) may be divided by support means(11) to hold packages of soft ice (12). Fans (13) are placed in thecompartment to provide circulation. FIG. 4a view of the support grids(14) having openings (15) in the supporting grid. The grids may havehorizontal supports (16) which will divide the space in the grids sothat smaller packages of soft ice may be used.

For providing cooling to animals, the support grids may be placed on thefloor or sides of the compartment. The amount of cooling can bepartially controlled by the amount of circulation in the compartment.While the cooling methods of the invention may be particularly usefulfor shipment of laboratory animals, the cooling means may also be quiteuseful for shipping animals to be butchered. Animals, especiallypoultry, can become ill and die during shipment. Breeding animals whobecome infected are much more likely to become ill and introduceinfections into the flock or herd if subjected to heated conditionsduring transport. Resulting infections may result in spread of diseasesto man.

EXAMPLE 2

1 kg of composition prepared according to the method of Example 1 wasplaced in the freezer at -15° C. for 4 hours. The ice so prepared wasremoved from the freezer and allowed to sit at a temperature of 12° C.to 15° C. The temperature was measured at intervals after removal fromthe freezer. The ice maintained a temperature of <0° C. for more thanthree hours. After 4 hours the temperature was only 8° C.

EXAMPLE 3

A composition is made in accord with the teachings of Example 1 using,in place of sodium sulfate, sodium chloride.

While other chlorides and sulfates such as zinc chloride, potassiumchloride and potassium sulfate may be used in accord with the teachingsof this disclosure, the sodium chloride and sodium sulfate are effectiveand less costly than other salts.

The packaging may be in any shape, including shapes described in thecited U.S. Patents incorporated herein by reference. When the packageconsists of an inner non-porous layer and an outer porous layer, the twolayers may be laminated together. In a preferred embodiment, the outerlayer is larger than the inner layer and extends beyond the inner layer.

The packaging may contain areas which contain none of the soft icefilling. Materials which impart stability to the final pack may be usedin all or part of the packaging.

EXAMPLE 4

An inner, non-porous bag of polyethylene having dimensions of 40 cm by40 cm is prepared having an opening in one of four side edges and threeedges of the bag forming the sides and bottom thermally sealed. The openedge forming the top is partially sealed by application of heat. Thecolloidal material prepared in Example 1 that has been allowed to sitfor 1 hour since preparation is poured into the unsealed opening intothe bag to fill the bag 1/2 full. Excess air is forced from the bag andthe opening is sealed thermally.

A bag 45 cm wide and 45 cm long of tightly woven nylon is preparedhaving an opening in one of four side edges. A seam is sewn on threeedges of the bag forming the sides and bottom. A second seam is sewnaround the sides and bottom of the bag 2.5 cm from the previously sewnseam at the edge of the bag. The polyethylene bag containing soft icecomposition is placed into the nylon bag. The edges of the open top ofthe bag are turned inside and the top of the bag is sewed closed. Asecond seam is sewed inside the first seam at the top of the outer bag.

The use of the double layer for the packaging provides a strong outerlayer that helps protect the bag of non-porous material. It is alsopossible to fuse the two layers by heat or to laminate the layerstogether. In that instance, the bag of laminated material may beprepared in accord with the instructions for the preparation of theinner layer. The opening may then be thermally sealed. The fabriccovering is more comfortable against the skin and is less prone toadhere to certain kinds of material such as super-cooled metal.

When the pack is to be used for medical treatment, or if flexibility isrequired for some other reason, such as when containers are to bewrapped in the packs, the pack will be more flexible if the packaging isnot too full. Some of the packs described below are particularly usefulwhen flexibility is required for wrapping around containers or bodyparts.

EXAMPLE 5

An elongated pack may be made which can be shaped to fit various partsof the body. Before filling, the pack comprises a water-proof envelopehaving a first and second side and, further, having an open end and aclosed end, said open end being sealable. The pack may, additionally, beequipped with straps or other fastening means to hold said pack inplace. Such means may be, for example, straps with buckling means. Thewater-proof envelope may be made of materials such as rubber or fabriclaminated to polymeric materials such as polyethylene. After fillingwith soft ice in the manner described in Example 4, the open end issealed by any suitable means such as a clasp, a sealing strip or byheat. The pack may then be frozen and used, then refrozen for reuserepeatedly.

The ends of the pack may be brought together or into close proximity toeach other by means of straps which may have buckling means or loop-likematerial engageable with a fastening tab. Referring to FIG. 5, theelongated pack having closed edges (20), an open end (24) with sealingstrips for closing (21) after the soft ice has been poured into thepackage, a strip of loop-like material on the first side (22) and astrip of material for accepting loops of loop-like material on thesecond side (23).

EXAMPLE 6

A pack which may be contoured to conform to a body contour such as thechin or a joint is useful. Such a pack is shown in FIG. 6. Said pack hasa central portion (30) and four radially extending portions (31, 32, 33,and 34). The relative arrangements of the central body portion and thefour radially extending portions forms a cross-shaped ice pack. One ofthe radially extending members has an opening (35) at the end to allowthe introduction of soft ice. The opening is opened and resealed withsuitable closure means (36) such as the device shown in U.S. Pat. No.4,532,353 by Hubbard, which is incorporated herein by reference in itsentirety, or a water-tight zipper arrangement. The pack is filled inaccord with the teachings of Example 4, with care taken to assure thatall of the extending portions are about half filed. If the pack isrelatively flat during cooling, it is easier to work with. However,should the soft ice become overly cold and hard, the pack may be kneadedwith the hands to make the pack more pliable. The pack may be held inplace with straps with fastening means. Strips (37) with VELCRO™ orsimilar loop-like materials (38) may be secured at sites (39) havingmeans for accepting loops of loop-like materials.

What is claimed is:
 1. A composition of matter comprising 70% to 85%water, 4-10% salt, 8-15% glycerine and 2-6% polyacrylamide.
 2. Acomposition of claim 1 wherein the salt is sodium chloride.
 3. Acomposition of claim 1 wherein the salt is sodium sulfate.
 4. A methodof preparing a colloidal composition of claim 1 comprising the stepsof:1. dissolving a salt which is a chloride or sulfate in water, 2.adding glycerine and polyacrylamide to the solution obtained in step 1,and
 3. mixing the composition obtained in step 2 until a colloidalsuspension is formed.
 5. A shipping compartment containing:1. supportmeans for holding packages and
 2. packages containing a colloidalcomposition of claim
 1. 6. A shipping compartment of claim 5 containing,additionally, air circulation means.
 7. A shipping compartment of claim6 wherein the support means are arranged in a vertical fashion and have,additionally, more than one horizontal support.
 8. A shippingcompartment of claim 5 wherein the support means are arranged in avertical fashion and have, additionally, more than one horizontalsupport.
 9. A method of producing a soft ice of claim 1 comprising thesteps of:1) dissolving salts in water, 2) adding to the water/saltsolution, glycerine and poly acrylamide, with or followed by mixing, and3) freezing the composition obtained in step
 2. 10. A method of claim 9wherein, after step 2, the composition obtained at the end of step 2 ispoured into a pack before freezing.